Re: [PATCH] NFC: nci: Add bounds checking in nci_hci_create_pipe()

[Simon Horman <horms@kernel.org>]

On Fri, Jan 17, 2025 at 12:38:41PM +0300, Dan Carpenter wrote:
> The "pipe" variable is a u8 which comes from the network.  If it's more
> than 127, then it results in memory corruption in the caller,
> nci_hci_connect_gate().
> 
> Cc: stable@vger.kernel.org
> Fixes: a1b0b9415817 ("NFC: nci: Create pipe on specific gate in nci_hci_connect_gate")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>

Hi Dan,

Based on your analysis, which I agree with, this looks good.

Reviewed-by: Simon Horman <horms@kernel.org>

But this is a limited review, as I am not sufficiently familiar with NFC
to go by much more than your analysis. A review by Krzysztof would be great.

> ---
>  net/nfc/nci/hci.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/nfc/nci/hci.c b/net/nfc/nci/hci.c
> index de175318a3a0..082ab66f120b 100644
> --- a/net/nfc/nci/hci.c
> +++ b/net/nfc/nci/hci.c
> @@ -542,6 +542,8 @@ static u8 nci_hci_create_pipe(struct nci_dev *ndev, u8 dest_host,
>  
>  	pr_debug("pipe created=%d\n", pipe);
>  
> +	if (pipe >= NCI_HCI_MAX_PIPES)
> +		pipe = NCI_HCI_INVALID_PIPE;

Ceci n'est pas une pipe [1]

>  	return pipe;
>  }

[1] https://en.wikipedia.org/wiki/The_Treachery_of_Images